Allometrically adjusted chair stand test cutoff points to identify sarcopenia in older Brazilian adults: A cross-validation study

Abstract Background: The decline in muscle strength with age is linked to impaired functional ability and increased fall risk, leading to fractures, hospitalization, and mortality. The European Working Group on Sarcopenia in Older People recommends muscle strength assessment, especially with respect to handgrip strength (HGS). The chair stand test (CST) is a practical alternative that measures quadriceps strength without additional equipment, although it is influenced by body size. The Purpose of this study is to cross-validate allometric adjustments in the 30-second CST (30-s CST) for identifying low muscle strength in older adults, contributing to a more accurate and practical assessment of sarcopenia. Methods: This cross-sectional study analyzed data from older Brazilian adults. Muscle strength was measured via the 30-s CST and normalized by body size through allometric adjustments. Functional limitations (< 400 m) were assessed via the six-minute walk test (6MWT). Results: Allometric normalization effectively removed body size effects on the 30-s CST results, with an AUC > 0.70 in the ROC analysis. This validated the cutoff points proposed previously. Conclusions: Allometric adjustments in the 30-s CST provide a robust method for identifying low muscle strength and functional limitations in older adults, irrespective of body size and variations in chair height.